4554-821K Fixed Inductor Equivalent & Substitute Parts

Part Overview

The 4554-821K is a fixed unshielded inductor manufactured by API Delevan Inc., rated at 820 µH inductance with a maximum current capacity of 350 mA and 1.8Ohm DC resistance. This through-hole radial component operates across a temperature range of -40°C to 85°C and is classified as Active product status. Substitute parts are identified to address inventory availability, extended operating temperature requirements, or enhanced compliance certifications while maintaining core electrical and mechanical specifications.

Key Parameters

Parameter	Value	Unit
Inductance	820	µH
Inductance Tolerance	±10	%
Current Rating	350	mA
DC Resistance (Max)	1.8	Ohm
Q Factor @ Test Frequency	20	@ 796 kHz
Self Resonant Frequency	1.5	MHz
Shielding Type	Unshielded	—
Core Material	Ferrite	—
Mounting Type	Through Hole	—
Package Type	Radial, Vertical Cylinder	—
Operating Temperature Range	-40°C to 85°C	—

Substitute Part Grouping Explanation

Substitution eligibility for the 4554-821K is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

Inductance value: 820 µH
Inductance tolerance: ±10%
DC resistance: 1.8Ohm maximum
Core material: Ferrite
Shielding configuration: Unshielded
Package type: Radial, Vertical Cylinder
Mounting type: Through Hole
Q factor @ 796 kHz: 20
Self resonant frequency: 1.5 MHz

Allowable Variation Parameters:

Current rating: Equal to or greater than 350 mA
Operating temperature range: Equal to or wider than -40°C to 85°C
Physical dimensions: Within mechanical compatibility for radial through-hole mounting
RoHS/REACH compliance: Enhanced compliance acceptable

The RL622-821K-RC from Bourns Inc. meets all mandatory matching parameters and exceeds the current rating specification (380 mA vs. 350 mA), providing direct substitution capability with improved thermal operating range (-55°C to 105°C) and RoHS3 compliance.

Parameter Comparison

Parameter	4554-821K (API Delevan)	RL622-821K-RC (Bourns)	Match Status
Inductance	820 µH	820 µH	Exact Match
Inductance Tolerance	±10%	±10%	Exact Match
Current Rating	350 mA	380 mA	Substitute Exceeds
DC Resistance (Max)	1.8 Ohm	1.8 Ohm	Exact Match
Q @ 796 kHz	20	20	Exact Match
Self Resonant Frequency	1.5 MHz	1.5 MHz	Exact Match
Core Material	Ferrite	Ferrite	Exact Match
Shielding	Unshielded	Unshielded	Exact Match
Mounting Type	Through Hole	Through Hole	Exact Match
Package Type	Radial, Vertical Cylinder	Radial, Vertical Cylinder	Exact Match
Operating Temperature	-40°C to 85°C	-55°C to 105°C	Substitute Exceeds
RoHS Status	Non-compliant	ROHS3 Compliant	Substitute Enhanced

Engineering Selection Recommendations

Primary Selection: 4554-821K Select the 4554-821K when the application operates within the specified temperature range (-40°C to 85°C) and RoHS compliance is not a design requirement. This component is Active status with 879 units in stock.

Substitute Selection: RL622-821K-RC Select the RL622-821K-RC when any of the following conditions apply:

Extended operating temperature range is required beyond 85°C
RoHS3 compliance is mandated by design specifications or customer requirements
Higher current margin is beneficial for thermal stress reduction (380 mA vs. 350 mA rating)
Extended inventory availability is prioritized (5896 units in stock)

Both components are Active status products. The RL622-821K-RC provides enhanced compliance certifications and thermal operating range while maintaining identical electrical performance across all critical parameters.

Frequently Asked Questions (FAQ)

Q: Can the RL622-821K-RC replace the 4554-821K in all applications?

A: The RL622-821K-RC is electrically and mechanically equivalent to the 4554-821K across all critical specifications: inductance (820 µH), tolerance (±10%), DC resistance (1.8Ohm), Q factor (20 @ 796 kHz), and self-resonant frequency (1.5 MHz). The substitute component exceeds the current rating (380 mA vs. 350 mA) and extends the operating temperature range (-55°C to 105°C vs. -40°C to 85°C). Direct substitution is valid for through-hole radial mounting applications.

Q: What are the physical dimension differences between these parts?

A: The 4554-821K has a diameter of 0.340" (8.64 mm) and seated height of 0.433" (11.00 mm). The RL622-821K-RC has a diameter of 0.335" (8.50 mm) and seated height of 0.433" (11.00 mm). Both components fit standard radial through-hole footprints with negligible dimensional variation.

Q: Is RoHS compliance a factor in selecting between these parts?

A: The 4554-821K is RoHS non-compliant. The RL622-821K-RC is ROHS3 compliant. If the application or customer requirement mandates RoHS compliance, the RL622-821K-RC is the required selection.

Q: What is the difference in core construction between these inductors?

A: Both components use ferrite core material. The 4554-821K is specified as a standard ferrite core inductor. The RL622-821K-RC is specified as a drum core, wirewound inductor with ferrite material. Both configurations deliver identical electrical performance at the specified test frequency (796 kHz) and operating conditions.

Q: Can these parts be used interchangeably in PCB designs?

A: Yes, both components are through-hole radial inductors with identical package types and compatible mechanical dimensions. PCB footprints designed for either component accommodate the other without modification. Lead spacing and hole diameter compatibility are maintained across both parts.

Q: Which part should be selected for new designs?

A: For new designs, the RL622-821K-RC is the preferred selection due to ROHS3 compliance, extended operating temperature range (-55°C to 105°C), and higher current rating (380 mA). The 4554-821K remains suitable for legacy designs or applications with specific temperature constraints within -40°C to 85°C.

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